A user wants to know how to check the SFDC API requests (calls) per 24-hour period for an Org?
The following table lists the limits for the total API requests (calls) per 24-hour period for an org.
To find the API Requests for the Last 24 Hours, go to Setup --> Administration Setup --> Company Profile --> Company Information.
To identify users and their API usage Click the Reports tab and view the "API Usage Last 7 Days" report under the Administrative Reports folder.
Salesforce Developer Limits Quick Reference: Salesforce Developer Limits Quick Reference: API Requests Limits